In the years before World War I thousands of letters handled by this country's postal service went undelivered. They ended up in the waste bin because they were addressed improperly or incompletely, or were illegible. When local postal workers were stumped about what to do with a letter they couldn't deliver they forwarded the stray mail to the Dead Letter Office.
About six percent of the dead mail handled around the turn of the century contained items of value. In one year, for example, 29,017 letters contained cash amounting to $42,064. Another 71,336 letters contained checks, postal notes, or money orders worth $2,308.046. Luckily with the help of the dead letter detectives, a good deal of this stray mail ultimately found its way home. During another year, 49,683 pieces of mail, including $2,190,422 worth of valuables, were returned.
Women were hired by the Post Office Department to work in the Dead Letter Office for a different reason. Postal officials felt that women had better analytical powers than men, and could therefore decipher complicated and confusing addresses far easier. There have been many exceptional letter detectives in the Dead Letter Office. The best of them was Mrs. Patti Lyle Collins, who worked for the Post Office Department at the turn of the century. Check out my postal history covers on ebay.